Flexible semi-bulk containers are well known in the prior art. They are used to contain flowable materials and when used with fluidized solids, slurries and liquids, a particular problem exists when they are shipped in less than truck load shipments. In such shipments, the packages or containers must have adequate stability to stand alone. Clearly, when a flexible container is filled with a fluidized material such as a liquid, they cannot stand alone unless supported against each other and the walls of some object such as a truck body or bed.
The containers may be constructed from a non-porous material, such as polyethylene, polypropylene, treated paper and the like, so that they can be stored and transported in an exposed condition without contamination of the material therein or without leakage. Because the containers are flexible, they can be collapsed when empty and reused several times if the situation warrants. However when such containers are filled with a fluidized material such as a liquid, they become unstable and tend to react to any motion imparted to them causing them to fall over, distort, change shape and the like.
The present invention overcomes the disadvantages of the prior art in relation to flexible semi-bulk containers which are used with fluidized solids, semi-solids, slurries and liquids by providing the container or package with adequate stability to stand alone when filled with the fluidized material. This is accomplished by the use of panels formed of rigid materials and that are associated with the flexible semi-bulk container. Such panels may be constructed of number of substantially inflexible materials including, but not limited to, hardboard, particle board, corrugated plastic, foamed plastic, solid state fiber (laminated chip board), plyboard and the like. Such panels are associated with the container side walls in such a way that rigidity is imparted to the side walls of the flexible container.
In one embodiment, the flexible container is formed with side walls having a double layer of material with a space between them. A rigid panel is inserted in the space in at least two of the opposing side walls of the container to provide stability to the container. In such case, the at least two opposing panels are scored longitudinally along the center of the panel or is otherwise hinged so that they can fold at the center. This allows the container to be folded, stored and shipped in the smallest possible position during non-use. The panels can be inserted in the spaces between the double layer side walls as the container is made or may be inserted later at the user's location. In the latter case, top or bottom seams can be left unsewn to allow the insertion. If the panels are inserted during the manufacturing of the container, all of the seams can be closed. Panels may be inserted in the space formed by each double layer wall in all four side walls of the container if desired. Again, however, at least two of the opposing side walls must have the score lines to enable the container to be folded during non-use.
Depending upon the type of material used for the rigid panels, the rigid panels may be attached to the inside of the container side walls by laminating the panels to the inside of each wall during manufacturing.
The panels may also be glued to the inside of the side walls as the container is being manufactured. Again, at least two opposing panels must be center scored or otherwise hinged to allow folding of the finished unit.
The invention also contemplates the use of a four-sided sleeve inserted within the flexible container to provide stability to the container when filled with a fluidized material. The sleeve comprises a continuous rectangular panel scored across its width at spaced locations so as to form a four-sided sleeve when folded along the score lines, two opposing sides of the sleeve having score lines thereon to enable folding of the container with the sleeve therein for storage and handling. The four-sided sleeve thus imparts stability to the container when filled with a fluidized material. If desired, the four-sided sleeve may be glued to the inside walls of the container.
The invention also contemplates the use of a composite liquid container that may be used inside any of the containers previously discussed that have rigidity imparted to them by the use of rigid panels as explained. Using any of those containers, a liner of co-extruded plastic film having a fill and a discharge spout for receiving and discharging a liquid, is inserted inside the container. It may or may not be glued in place. With such properly made liner, the containers are useable for a variety of semi-solids and liquids.
The flexible semi-bulk containers can be manufactured of any flexible material with adequate tensile strength including and not limited to reinforced paper, woven polypropylene, woven polyethylene, polyester fabric, burlap fabric, vinyl coated polyester and spun bonded non-woven fabrics. Any fabric of natural or synthetic fiber or a combination thereof can be used.